Display device

ABSTRACT

A display device according to the present invention includes a display region arranged with a plurality of pixels, and a sealing layer covering the display region, wherein the sealing layer includes an insulation layer having a density pattern, the density pattern is a pattern including a low density region and a high density region, the low density region has the insulation layer with a lower density than an average density within the display region of the insulation layer, and the high density region has the insulation layer with a higher density than an average density within the display region of the insulation layer.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 2016-144198, filed on Jul. 22,2016, the entire contents of which are incorporated herein by reference.

FIELD

The present invention is related to a display device and a method ofmanufacturing the display device. Specifically, the present invention isrelated to an organic electroluminescence (referred to herein as organicEL) display device and a method of manufacturing the display device.

BACKGROUND

An organic EL display device is arranged with a light emitting elementin each pixel and an image is displayed by individually controlling theemitted light. A light emitting element includes a structure in which alayer (referred to herein as [light emitting layer]) including anorganic EL material is sandwiched between a pair of anodes, onedistinguished as an anode and the other as a cathode. When electrons areinjected to the light emitting layer from the cathode and holes areinjected from the anode, the electrons and hole recombine. Lightemitting molecules within the light emitting layer are excited bysurplus energy discharged thereby and light is subsequently emitted byde-excitation.

In an organic EL display device, the anode of each light emittingelement is arranged as a pixel electrode for each pixel and the cathodeis arranged as a common electrode across a plurality of pixels andapplied with a common potential. The organic EL display device controlslight emission of a pixel by applying the potential of a pixel electrodeto each pixel with respect to the potential of the common electrode.Furthermore, the cathode may be arranged in each pixel and in this caseit is not necessary that a common potential is applied to all pixels.

However, a light emitting layer of an organic EL display device iseasily degraded by the infiltration of water and a problem existswhereby a non-lighting region called a dark spot is produced. In orderto solve such a problem, a sealing layer for preventing the infiltrationof water is arranged in many organic EL display devices.

For example, an organic light emitting display device is disclosed inJapanese Laid Open Patent Publication No. 2010-027561 arranged with asubstrate, a display part formed above the substrate, a sealing filmcovering the display part and a non-light emitting region of theperiphery side of the display part and the density and thickness ofwhich increases from the center part to an edge part. In this way, thelifetime of an organic light emitting display device is increased bypreventing water or oxygen from permeating in a side surface direction.

In recent years, flexible display devices are actively being developedin which display regions can be bent. While a sealing layer arranged ina flexible display device has high barrier properties at high densities,cracks may easily occur when a sealing layer is bent. Since cracks whichoccur in a sealing layer can become a water infiltration path,reliability of a display device drops.

SUMMARY

A display device according to one embodiment of the present inventionincludes a display region arranged with a plurality of pixels, and asealing layer covering the display region, wherein the sealing layerincludes an insulation layer having a density pattern, the densitypattern is a pattern including a low density region and a high densityregion, the low density region has the insulation layer with a lowerdensity than an average density within the display region of theinsulation layer, and the high density region has the insulation layerwith a higher density than an average density within the display regionof the insulation layer.

A manufacturing method of a display device according to one embodimentof the present invention includes preparing an array substrate havingflexibility and arranged with a plurality of pixels in a display region,and forming an inorganic insulation layer covering the plurality ofpixels using a roll coater, wherein the inorganic insulation layer isformed so that a density pattern is included having a low density regionand a high density region, the low density region has the inorganicinsulation layer with a lower density than an average density within thedisplay region of the inorganic insulation layer, and the high densityregion has the inorganic insulation layer with a higher density than anaverage density within the display region of the inorganic insulationlayer.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is perspective view diagram for explaining an approximatestructure of a display device related to one embodiment of the presentinvention;

FIG. 2A is a planar view diagram and a cross-sectional diagram forexplaining a structure of a display device related to one embodiment ofthe present invention;

FIG. 2B is a planar view diagram and a cross-sectional diagram forexplaining a bent state of a display device related to one embodiment ofthe present invention;

FIG. 3 is an expanded cross-sectional diagram for explaining a structureof a display device related to one embodiment of the present invention;

FIG. 4A is a cross-sectional diagram for explaining a manufacturingmethod of a display device related to one embodiment of the presentinvention;

FIG. 4B is a cross-sectional diagram for explaining a manufacturingmethod of a display device related to one embodiment of the presentinvention;

FIG. 4C is a cross-sectional diagram for explaining a manufacturingmethod of a display device related to one embodiment of the presentinvention;

FIG. 5 is schematic diagram for explaining a structure of a film formingapparatus used in a method of manufacturing a display device related toone embodiment of the present invention;

FIG. 6 is schematic diagram for explaining a structure of a film formingapparatus used in a modified example of a method of manufacturing adisplay device related to one embodiment of the present invention;

FIG. 7 is a cross-sectional diagram for explaining a structure of adisplay device related to one embodiment of the present invention;

FIG. 8 is a planar view diagram for explaining a structure of a displaydevice related to one embodiment of the present invention; and

FIG. 9 is a planar view diagram and cross-sectional diagram forexplaining a structure of a display device related to one embodiment ofthe present invention.

DESCRIPTION OF EMBODIMENTS

A display device related to a number of embodiments of the presentinvention is explained in detail below while referring to the diagrams.However, the display device of the present invention should not belimited to the embodiments below and it is possible to perform thepresent invention using various modifications. In all of theembodiments, the same reference symbols are attached to similarelements. In addition, the dimension ratios in the drawings may bedifferent from actual ratios and parts of the structure may be omittedfrom the drawings.

First Embodiment [External Structure]

FIG. 1 is perspective view diagram for explaining an external structureof a display device 100 related to the present embodiment. The externalstructure of the display device 100 related to the present embodiment isexplained using FIG. 1.

The display device 100 related to the present embodiment includes anarray substrate 102, an opposing substrate 106 and a plurality ofconnection terminals 109.

The array substrate 102 includes at least a first substrate 104 and aplurality of pixels 110.

The first substrate 104 has flexibility. Although a specific materialfor the substrate having flexibility is described herein, a resinmaterial is used. A display region 104 a and a terminal region 104 b arearranged above the first substrate 104.

The plurality of pixels 110 is arranged within the display region 104 aof the first substrate 104. In the present embodiment, the plurality ofpixels 110 is arranged in a matrix. Although not shown in FIG. 1, eachof the plurality of pixels 110 is formed from a pixel circuit includingat least a selection transistor, a drive transistor and a light emittingelement.

The opposing substrate 106 includes at least a second substrate 108.

The second substrate 108 has flexibility. It is possible to use the samesubstrate as the first substrate 104 as a substrate having flexibility.The second substrate 108 is arranged opposing the first substrate 104 onan upper surface of the display region 104 a. The second substrate 108is fixed to the first substrate 104 by a sealing member 130 whichencloses the display region 104 a. The display region 104 a arranged inthe first substrate 104 is sealed by the second substrate 108 andsealing member 130 so that it is not exposed to the air. By adoptingsuch a sealing structure, degradation of a light emitting element ineach of the plurality of pixels 110 is suppressed.

The opposing substrate 106 may further include a color filter, a lightblocking layer, a polarization plate and a phase plate and the like.

A color filter is arranged at a position opposing each of the pluralityof pixels 110. A light blocking layer (also called a black matrix) isarranged at a position which demarcates each of the plurality of pixels110.

A polarization plate and phase plate cover the plurality of pixels 110and are arranged on the opposing substrate 106 side. The polarizationplate and phase plate are arranged in order to suppress degradation invisibility due to external light which enters the display device 100being reflected by a pixel electrode.

The plurality of connection terminals 109 is arranged within theterminal region 104 b. A plurality of terminal regions 104 b is arrangedon one end part of the first substrate 104 and the outer side of thesecond substrate 108. A wiring substrate (not shown in the diagram)which connects devices which output an image signal or a power sourcewith the display device 100 is arranged in the plurality of connectionterminals 109. A connection point between the wiring substrate and theplurality of connection terminals 109 is exposed to the exterior.

[Detailed Structure]

FIG. 2A is a planar view diagram and a cross-sectional diagram forexplaining an approximate structure of a display device 100 related tothe present embodiment. FIG. 2B is a perspective diagram for explainingthe bent state of the display device 100 related to the presentembodiment. FIG. 3 is an expanded cross-sectional diagram for explainingthe structure of the display device 100 related to the presentembodiment. Although described herein, a display region includes a lowdensity region 126 a and a high density region 126 b. In FIG. 3, across-sectional diagram of a low density region 126 a of the displaydevice 100 is shown at the top and a cross-sectional diagram of a highdensity region 126 b of the display device 100 is shown at the bottom.

The display device 100 related to the present embodiment is arrangedwith an array substrate 102 and a sealing layer 120.

The array substrate 102 includes the first substrate 104 and a pluralityof pixels 110.

The first substrate 104 includes a display region 140 a and a terminalregion 140 b. The first substrate 104 uses a substrate havingflexibility in the present embodiment. A resin material is used as thesubstrate having flexibility. It is preferred that a high molecularmaterial including an imide bond in repeating units is used as the resinmaterial such as polyimide for example. Specifically, a film substratein which polyimide is formed into a sheet shape is used as the firstsubstrate 104. In this way, the entire array substrate 102 hasflexibility.

Each of the plurality of pixels 110 is arranged in the display region140 a above the first substrate 104. Each of the plurality of pixels 110is formed from a pixel circuit including at least a selection transistor(not shown in the diagram), a drive transistor (not shown in thediagram), and a light emitting element 112.

It is possible to use a self-light emitting type light emitting elementas the light emitting element 112, for example it is possible to use anorganic EL light emitting element. The organic EL light emitting elementincludes a pixel electrode 114, a common electrode 116 and a lightemitting layer 118.

The pixel electrode 114 is arranged for each of the plurality of pixels110. It is preferred to use a material including a metal layer with highreflectance as the material of the pixel electrode 114 in order toreflect light emitted by the light emitting layer 118 to the commonelectrode 116 side. It is possible to use silver (Ag) for example as themetal layer with high reflectance.

Furthermore, a transparent conductive layer may be stacked in additionto the metal layer with high reflectance described above. ITO (indiumoxide added with tin) or IZO (indium zinc oxide) and the like which havetranslucency and conductivity are preferred to be used as thetransparent conductive layer. In addition, an arbitrary combination ofthese may also be used.

The common electrode 116 in the present embodiment is arranged across aplurality of pixels 110. ITO (indium oxide added with tin) or IZO(indium zinc oxide) and the like which have translucency andconductivity are preferred to be used as the material of the commonelectrode 116 in order to allow light emitted by the light emittinglayer 118 to pass through. Alternatively, a metal layer having a filmthickness which can allow emitted light to pass though may also be usedas the common electrode 116. Furthermore, a common electrode may also beindividually formed for each pixel electrode.

The light emitting layer 118 is arranged held between a pixel electrode114 and common electrode 116. An organic EL material which emits lightwhen supplied with a current is used as the material of the lightemitting layer 118. It is possible to use a low molecular or highmolecular organic material as the organic EL material. In the case wherea low molecular organic material is used, in addition to an organicmaterial having light emitting properties, the light emitting layer 118is formed including a hole injection layer or electron injection layeror a hole transport layer or electron transport layer in order to holdan organic material having light emitting properties.

A bank 128 is arranged between two adjacent pixels 110. The bank 128 isarranged to cover a periphery edge part of a common electrode 114.

It is preferred to use an insulation material as the material of thebank 128. It is possible to use an inorganic insulation material or anorganic insulation material as the insulation material. It is possibleto use silicon oxide, silicon nitride or a combination thereof forexample as an inorganic insulation material. It is possible to use apolyimide resin, an acrylic resin or a combination thereof for exampleas an organic insulation material. An inorganic insulation material andorganic insulation material may also be used in combination.

By arranging the bank 128 formed from an insulation material, it ispossible to prevent a common electrode 116 and pixel electrode 114 fromshort circuiting at an end part of the pixel electrode 114. Furthermore,it is possible to securely insulate adjacent pixels 110.

The sealing layer 120 is arranged across the display region 140 acovering a plurality of pixels 110.

In the present embodiment, the sealing layer 120 includes a firstinsulation layer 122, second insulation layer 124 and third insulationlayer 126. These layers which form the sealing layer 120 are stackedfrom the bottom layer in the order first insulation layer 122, secondinsulation layer 124 and third insulation layer 126. These layers areexplained in order from the bottom layer side.

The first insulation layer 122 is arranged on the lowest layer in thesealing layer 120. An insulation material with low moisture permeabilityis preferred as the material of the first insulation layer 122.

It is possible to use an inorganic insulation layer as a specificmaterial of the first insulation layer 122. For example, it is possibleto use a layer such as silicon oxide (SiOx), silicon nitride (SiNx),silicon oxynitride (SiOxNy), silicon nitride oxide (SiNxOy), aluminumoxide (AlOx), aluminum nitride (AlNx), aluminum oxynitride (AlOxNy) andaluminum nitride oxide (AlNxOy) and the like (x, y are arbitrary) as aspecific material of an inorganic insulation layer. In addition, astructure in which these layers are stacked may be used. In the presentembodiment, silicon nitride is used as the material of the firstinsulation layer 122.

The second insulation layer 124 is arranged above the first insulationlayer 122. An insulation material which can flatten concave and convexparts caused by a plurality of light emitting elements 112 or banks 128and the like arranged on a lower layer is preferred as the material ofthe second insulation layer 124. When such concave and convex partsexist, the covering properties of the first insulation layer 122 are nolonger sufficient and it becomes easier for a transport path of water tothe first insulation layer 122 to be produced.

It is possible to use an inorganic insulation layer or organicinsulation layer as a specific material of the second insulation layer124. It is possible to use the inorganic insulation layers mentionedabove as the inorganic insulation layer. It is possible to use anacrylic resin or epoxy resin and the like for example as the organicinsulation layer.

An acrylic resin is used as the material of the second insulation layer124 in the present embodiment.

The third insulation layer 126 is arranged above the second insulationlayer 124. An insulation material with low moisture permeability ispreferred as the material of the third insulation layer 126. Although anacrylic resin is used as the second insulation layer 124 in the presentembodiment, an organic insulation layer easily becomes an infiltrationpath for water. As a result, when water infiltrates the secondinsulation layer 124, there is concern that the water may reach thefirst insulation layer 122 and further infiltrate to the light emittinglayer 118. Since the second insulation layer 124 using an acrylic resinhas a high level of flatness, the third insulation layer 126 hasexcellent covering properties which makes it difficult for a transportpath for water to be produced.

In the present embodiment, silicon nitride is used as the material ofthe third insulation layer 126.

The third insulation layer 126 further includes a density pattern. Here,a density pattern means a pattern including the low density region 126 aand high density region 126 b. This pattern may also be a cyclicalpattern. The low density region 126 a is a region in which the densityof the third insulation layer 126 has a lower density than the averagedensity of the third insulation layer 126 arranged across and within thedisplay region. The high density region 126 b is a region in which thedensity of the third insulation layer 126 has a higher density than theaverage density of the third insulation layer 126 arranged across andwithin the display region. Here, density may mean area volume density(in units of atoms/cm2) or may mean volume density (in units ofatoms/cm3). The case where the contained amount of hydrogen changes infurther included.

Furthermore, a density pattern is not limited to including a clearcontrast in which a local density distribution within each regionchanges in a step shape in a boundary vicinity of the low density region126 a and high density region 126 b. Therefore, a density pattern alsoincludes the case where the density distribution changes linearly forexample.

In the present embodiment, the contained amount of hydrogen of the thirdinsulation layer 126 within the high density region 126 b is 5 at % ormore and 15 at % or less, and the contained amount of hydrogen withinthe low density region 126 a is 30 at % or more.

In the present embodiment, the density pattern is a band shape in avertical direction. The width of each of the low density region 126 aand the high density region 126 b is almost equal.

By adopting such a structure, the low density region 126 a functions asan impact absorbing layer when the display device 100 is bent and it ispossible to relieve stress applied to the high density region 126 b. Inthis way, it is difficult for cracks to occur in the sealing layer 120when the display device 100 is bent and it is possible to provide thedisplay device 100 with improved reliability.

The width of each of the high density region 126 b and low densityregion 126 a may be determined based on the minimum curvature radiuswhich is assumed when the display device 100 is bent. When the width ofeach of the high density region 126 b and low density region 126 a islarge compared to the curvature radius described above, stress producedin the third insulation layer 126 when bent is not dispersed and the lowdensity region 126 a of the third insulation layer 126 no longerperforms the role of an impact absorbing layer. As a result, resistanceto cracks when bending cannot be improved.

Furthermore, in the present embodiment, a band shaped repeating patternhas a constant cycle as the density pattern. However, the densitypattern is not limited thereto. As another example, in the case where aplanar region in which bending is not assumed and a curved region wherebending is assumed are stipulated within a display region, a densitypattern may be arranged only in the curved region. As a further example,although a density pattern is arranged in both a curved region and aplanar region, the cycle of a density pattern in a planar region withrespect to the cycle of a density pattern in the curved region may beset to become larger as the distance increases from a boundary with thecurved region.

According to the display device 100 related to the present embodiment,it is possible to provide the display device 100 with improvedresistance to bending of the display device 100.

[Manufacturing Method]

FIG. 4A to FIG. 4C are cross-sectional diagrams for explaining amanufacturing method of the display device 100 related to the presentembodiment. A manufacturing method of the display device 100 related tothe present embodiment is explained in detail using FIG. 4A to FIG. 4C.The manufacturing method of the display device 100 related to thepresent embodiment includes the following processes.

First, an array substrate 102 arranged with a plurality of pixels 110 inthe first substrate 104 is prepared (FIG. 4A).

The first substrate 104 is a substrate having flexibility formed bymolding a polyimide resin and the like into a sheet shape above asupport substrate made of a glass substrate and the like. As a result,the entire array substrate 102 includes flexibility. A plurality ofpixels 110 is formed above the first substrate 104.

Next, the first insulation layer 122 and second insulation layer 124 areformed covering the plurality of pixels 110 (FIG. 4B). The material ofthe first insulation layer 122 is silicon nitride and it is possible touse a plasma CVD method or sputtering method as the film formationmethod. The second insulation layer 124 is an acrylic resin and it ispossible to use a coating method or vapor deposition method as the filmformation method.

Next, the third inorganic insulation layer 126 is formed having adensity pattern including a low density region 126 a and high densityregion 126 b covering the plurality of pixels 110 (FIG. 4C). It ispossible to use a roll coater 500 as the film formation apparatus of thethird insulation layer. It is possible to use a plasma CVD method forexample as the film formation method.

FIG. 5 is a schematic diagram for explaining the structure of a rollcoater 500 used in the manufacturing method of the display device 100related to the present embodiment. The array substrate 102 havingflexibility is transported to a winding roll 506 from a feed roll 504within a film formation chamber 502. The array substrate 102 passesthrough two film formation rolls 508 between the feed roll 504 andwinding roll 506. A plasma P is generated between the two film formationrolls 508 and film formation takes place. In this way, the arraysubstrate 102 is transported and a film formation material is depositedin the vicinity of sections where the two film formation rolls 508 areclosest. In this way, it is possible to deposit a film formationmaterial across the film formation surface of the array substrate 102.

In order to obtain the third insulation layer 126 having the densitypattern related to the present embodiment using the roll coater 500, thefilm formation conditions may be dynamically changed according to thetransportation speed of the array substrate 102 and the cycle determinedby a band gap included in a certain density pattern. The film formationconditions are, for example, film formation gas flow amount, filmformation temperature and pressure and the like.

That is, the film formation conditions are switched between a timeperiod in which a region corresponding to the low density pattern 126 ais transported through the vicinity of a position where the two filmformation rolls 508 are closest to each other, and a time period inwhich a region corresponding to the high density pattern 126 b istransported through the vicinity of a position where the two filmformation rolls 508 are closest to each other when transporting thearray substrate 102. In this way, it is possible to obtain the thirdinsulation layer 126 having a band shaped density pattern in the samedirection as the rotation axis of the film formation roll 508.

Next, the array substrate 102 and opposing substrate 106 are bondedtogether and it is possible to obtain the display device 100 related tothe present embodiment shown in FIG. 2A and FIG. 2B.

According to the manufacturing method of the display device 100 relatedto the present embodiment, it is possible to obtain the third insulationlayer 126 having a band shaped density pattern in the same direction asthe rotation axis of the film formation roll 508 included in a rollcoater.

Modified Example

It is possible to form the third insulation layer 126 using a sputteringmethod instead of a plasma CVD method as a modified example of themanufacturing method of the display device 100 related to the presentembodiment.

FIG. 6 is a schematic diagram for explaining the structure of a rollcoater 600 used in a modified example of the manufacturing method of thedisplay device 100 related to the present embodiment. The arraysubstrate 102 having flexibility is transported to a winding roll 606from a feed roll 604 within a film formation chamber 602. The arraysubstrate 102 passes through two film formation rolls 608 between thefeed roll 604 and winding roll 606. One direction of the film formationroll 608 is installed with a sputtering target 610. In this way, thearray substrate 102 is transported and a film formation material isdeposited in the vicinity of sections where the sputtering target 610and film formation roll 608 are closest. In this way, it is possible todeposit a film formation material across the film formation surface ofthe array substrate 102.

In order to obtain the third insulation layer 126 having the densitypattern related to the present embodiment using the roll coater 600, thefilm formation conditions may be dynamically changed according to thetransportation speed of the array substrate 102 and the cycle determinedby a band gap included in a certain density pattern. The film formationconditions are for example, film formation gas flow amount, filmformation temperature and pressure and the like.

Second Embodiment [Detailed Structure]

FIG. 7 is a cross-sectional diagram for explaining an approximatestructure of a display device 200 related to the present embodiment. Thedisplay device 200 related to the present embodiment is differentcompared to the display device 100 related to the first embodiment onlyin the structure of the third insulation layer 126 of the sealing layer120 in particular.

The sealing layer 120 includes the first insulation layer 122 to thethird insulation layer 126 and the third insulation layer 126 includes aplurality of insulation layers. In the third insulation layer 126, aninsulation layer which includes a first density pattern and aninsulation layer which includes a second density pattern are alternatelystacked.

The second density pattern is an inverted pattern of the first densitypattern. That is, in a plane structure, the high density region 126 b inthe second density pattern corresponds to the low density region 126 ain the first density pattern, and the low density region 126 a in thesecond density pattern corresponds to the high density region 126 b inthe first density pattern. In this way, in two adjacent insulationlayers in a cross-sectional structure, the high density region 126 b inone insulation layer is adjacent to the low density region 126 a in theother insulation layer.

By adopting such a structure, at least one insulation layer arrangedwith a high density region 126 b exists above an arbitrary section on aplane surface of the array substrate 102. In this way, a path in a filmthickness direction within a path of water which can be produced in thesealing layer 120 is blocked since a high density region 126 b exists inat least one layer.

In addition to the structure described above, it is further preferablethat a structure is adopted in which a path in a plane direction isblocked within a path of water which can be produced in the sealinglayer 120. In the present embodiment, a path of water from the exteriorof the sealing layer 120 to the plurality of pixels 110 is blocked inboth a film thickness direction and plane direction by a high densityregion 126 b in at least the lowest insulation layer and a high densityregion 126 b in an adjacent insulation layer thereupon.

In this way, moisture permeability of the sealing layer 120 as a wholedrops. In other words, water prevention of the sealing layer 120 as awhole improves. In this way, it is possible to provide the displaydevice 200 with improved reliability.

Furthermore, a form in which density patterns in a mutually invertedrelationship are stacked was shown in the present embodiment. However,needless to say, the present embodiment is not limited to the structureof the sealing layer 120 described above in order to obtain the actionsand effects described above.

According to the display device 200 related to the present embodiment,it is possible to provide the display device 200 with improvedresistance to bending and improved water prevention.

Third Embodiment [Detailed Structure]

FIG. 8 is a planar view diagram for explaining an approximate structureof a display device 300 related to the present embodiment. The displaydevice 300 related to the present embodiment is different compared tothe display device 100 related to the first embodiment only in thedensity pattern. That is, in the display device 300 related to thepresent embodiment, a plurality of punctuated high density regions 126 bis repeatedly arranged in a plane direction. That is, a plurality ofpunctuated high density regions 126 b is arranged in a lattice shapein-plane.

In addition, although a density pattern has a limited repeating cycle ina horizontal direction in the display device 100 related to the firstembodiment, the density pattern has translational symmetry in a verticaldirection. In the display device 300 related to the present embodiment,a density pattern has a limited repeating cycle in a horizontaldirection and a vertical direction and the cycles are equal in bothdirections.

By adopting such a structure, resistance to bending improves not only ina vertical direction and horizontal direction but also in otherarbitrary directions.

Furthermore, in the present embodiment, a form in which a plurality ofpunctuated high density regions 126 b is shown as being arranged in alattice shape in-plane. However, the present invention is not limited tothis form and various modifications are possible. For example, not onlya punctuated shape but an arbitrary closed curve is also possible. Inaddition, not only a lattice shape but a plurality of high densityregions 126 b may also be arranged to have a repeating cycle withrespect to two arbitrary directions having mutual angles.

According to the display device 300 related to the present embodiment,it is possible to provide the display device 300 with improvedresistance to bending in an arbitrary direction.

[Manufacturing Method]

First, an array substrate 102 arranged with a plurality of pixels 110 inthe first substrate 104 is prepared the same as in FIG. 4A.

Next, the same as in FIG. 4B, the first insulation layer 122 and secondinsulation layer 124 are formed.

Next, the third insulation layer 126 is formed above the array substrate102. In the present embodiment, the array substrate 102 is disposed in asubstrate support body. During film formation of the third insulationlayer 126 having a density pattern, a body including a temperaturegradient with a certain pattern is used as the substrate support body.

A certain pattern means a pattern based on a density pattern.Specifically, a temperature gradient is arranged so that in thesubstrate support body, the temperature of a region corresponding to ahigh density pattern 126 b is lower than the temperature of a regioncorresponding to a low density pattern 126 a. The layout of a heaterarranged in the substrate support body may be adjusted for example inorder to arrange a temperature gradient. A plasma CVD method can be usedfor example as the film formation method.

By arranging a temperature gradient in the substrate support body, adensity pattern with different film densities is formed according to thetemperature gradient in the third insulation layer 126 to be depositedeven in the case where other film formation conditions (pressure, gastype, plasma conditions and the like) are the same. Since depositionspeed increases the higher the temperature of a film formation surfaceof the array substrate 102, the density of a layer to be deposited canalso increase. In addition, since the amount of contained hydrogenincluded in the third insulation layer 126 drops the higher thetemperature of a film formation surface of the array substrate 102, thedensity of a layer to be deposited can also increase.

It is possible to form the third insulation layer 126 having a densitypattern corresponding to a certain pattern above a plurality of pixels110 in a state where this type of temperature gradient is arranged.

Next, the array substrate 102 and opposing substrate 106 are bondedtogether and it is possible to obtain the display device 300 related tothe present embodiment.

According to the manufacturing method of the display device 300 relatedto the present embodiment, it is possible to obtain a third insulationlayer 126 having an arbitrary density pattern.

Fourth Embodiment [Detailed Structure]

FIG. 9 is a planar view diagram and cross-sectional diagram forexplaining an approximate structure of a display device 400 related tothe present embodiment. The display device 400 related to the presentembodiment is different compared to the display device 200 related tothe second embodiment only in the density pattern. That is, in thedisplay device 400 related to the present embodiment, a first densitypattern is arranged with a plurality of high density regions 126 b andlow density regions 126 a repeatedly in a lattice shape.

By adopting such a structure, moisture permeability of the sealing layer120 as a whole drops. That is, water prevention of the sealing layer 120as a whole improves. Furthermore, resistance to bending improves notonly in a vertical direction and horizontal direction but also in otherarbitrary directions.

According to the structure of the display device 400 related to thepresent embodiment, it is possible to provide the display device 400with improved resistance to bending in an arbitrary direction andimproved water prevention.

The preferred forms of the present invention were explained above.However, these are merely examples and the technical scope of thepresent invention is not limited to these forms. A person ordinarilyskilled in the art could perform various modifications without departingfrom the concept of the present invention. Consequently, suchmodifications should naturally be interpreted as belonging to thetechnical scope of the present invention.

What is claimed is:
 1. A display device comprising: a display region arranged with a plurality of pixels; and a sealing layer covering the display region; wherein the sealing layer includes an insulation layer having a density pattern; the density pattern is a pattern including a low density region and a high density region; and the density pattern is a cyclical pattern. 